Device radio-based danger warning

ABSTRACT

In a radio-based device for issuing hazard warnings to the driver of a vehicle a data receiver situated on board the vehicle receives hazard data from a data transmitter of at least one other vehicle, and evaluates the received data in a computer unit. The received data includes information about the position, speed and direction of travel of the transmitting vehicle. According to the invention, from the received data of the transmitting vehicle and from information relating to the position, speed and direction of travel data of the receiving vehicle, a relevance measure is determined in the receiving vehicle, which relates to whether the transmitting vehicle is located on a section of road lying ahead of the receiving vehicle. A chronological profile of the relevance measure is determined by repeatedly determining the relevance measure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to co-pending application Ser. No. ______,filed Mar. 3, 2005 and assigned to the same assignee.

BACKGROUND AND SUMMARY OF THE INVENTION

This application claims the priority of German patent document 102 41134.4, filed Sep. 3, 2002 (PCT International Application No.PCT/EP2003/009330, filed Aug. 22, 2003), the disclosure of which isexpressly incorporated by reference herein.

The present invention relates to a device for radio-based issuance ofhazard warnings to a vehicle operator.

European patent document EP 927 983 A2 discloses such a system forradio-based issuance of hazard warnings in which vehicles are equippedwith data transmitters and receivers in order to exchange hazard warningdata. After the data transmitter has been activated, data relating tothe hazard are transmitted to other motor vehicles, together withinformation relating to the position, speed and direction of travel ofthe transmitting vehicle. In the receiving vehicle, the received dataare evaluated to determine whether or not a hazard lies ahead, and ifso, warning signals are conveyed to the driver.

French patent document FR 2 793 056 describes a device for issuinghazard warnings, in which the type of hazard is indicated in thevehicle. In the receiving vehicle it is determined whether it isnecessary to output the warning to other vehicles.

International patent document WO 01/61668 A1 discloses a hazard warningdevice, in which a warning zone is generated in the transmitting vehicleand is output together with the hazard warning. In the transmittingvehicle, the position of the vehicle and the type of road on which thevehicle is located are determined using a navigation system. Thedifference between the speed of the transmitting vehicle and the typicalor maximum speed of other vehicles on the given type of road is includedin the calculation of the warning zone in the transmitting vehicle. Thereceived hazard warning is evaluated in the receiving vehicle using anavigation system by checking whether the receiving vehicle is in thewarning zone and whether the hazard warning relates to a section of roadwhich possibly lies in front of the receiving vehicle.

The document “WARN—ein neues funkbasiertes Gefahrenwarnsystem im Kfz fürmehr Sicherheit im Straβenverkehr” [WARN—a new radio-based hazardwarning system in motor vehicles for providing more safety in roadtraffic], Brenzel, C., Hickel, F., Paβmann, C., VDI Berichte [VDIReports] No. 1415, 1998 discloses that, together with the hazardwarning, the type of hazard, the speed of the transmitting vehicle andinformation about the position of the transmitting vehicle can betransmitted. In the receiving vehicle, the difference in speed relativeto the transmitting vehicle is determined, and information about theposition of vehicles is used to determine whether the warning messagehas been generated by a vehicle traveling in front, by a vehicle behind,or by the oncoming traffic.

In “Wireless Vehicle to Vehicle Warning System”, Paβmann, C., Brenzel,C., Meschenmoser R., SAE Paper, 2000-01-1307, a check is made in thereceiving vehicle as to whether the transmitting vehicle is located infront of or behind the receiving vehicle.

German patent document DE 199 52 392 A1 discloses a method in whichwarning information that is dependent on the route is made available tothe driver. Digital road maps are used to detect, for example, whetherthe driver is approaching a curve. If so, and if the current speed ofthe vehicle is higher than a speed limit for the curve, the driver isfirst warned visually. If he or she does not react to the visual warningwithin a certain time, (i.e., if he or she continues to drive withundiminished speed), an additional audible warning is issued. Since thecurve has a fixed position, its approach is always detected at asufficiently large distance, and various warning stages of increasingurgency are successively triggered.

One object of the present invention is to provide an improved device forissuing warnings of hazards with improved detection of relevant hazardwarnings.

This and other objects and advantages are achieved by the hazard warningsystem according to the invention, which generates a hazard warning thatextends beyond the visual range of a hazard warning system, providing anelectronic lengthening of the classic hazard warning system. Asignificant component of the device is a radio modem which permits thedirect exchange of data between vehicles in real time and with asufficiently large range (for example, approximately 1 km). In addition,the device may also include a locating module with which the position ofthe vehicle can be determined by locating means. The locating module maybe a component of a navigation system, or it may be connected to anavigation system, in which case the position of the vehicle can bedetermined with even greater accuracy because the measured position ofthe vehicle can be represented on the digital map which is present inthe navigation system by map matching. As a result, errors in theposition determination can be compensated by the locating module.

The data which are received by the transmitting vehicle comprises hereinformation on the position of the transmitting vehicle, determined by alocating device and/or a directional course of the vehicle. Adirectional course of the vehicle is formed from the direction of traveland speed of the vehicle at various times. The received informationrelating to the position optionally also includes additional informationabout earlier positions of the transmitting vehicle. The earlierpositions of the vehicle form a position chain of the vehicle which iscomposed of a sequence of points at which information relating to theposition of the vehicle is present. In this context, the position chaincan be a directional course and/or a sequence of positions which aredetermined by a locating system or navigation system.

A relevance measure, which is determined from the received data of thetransmitting vehicle and the position, speed and direction of traveldata of the receiving vehicle, expresses the probability that thetransmitting vehicle is located on the section of road lying in front of(that is, downstream of) the receiver. The receiving vehicleadvantageously has information about the route, which is used toestimate in advance the future route of the receiving vehicle. Therelevance measure, which expresses the probability that the transmittingvehicle is located on the predicted future route of the receivingvehicle, is advantageously determined from the data received from thetransmitting vehicle, together with the predicted future route of thereceiving vehicle. Determining the chronological profile of therelevance measure makes possible more reliable detection of relevantlocations of hazards.

In one advantageous embodiment of the invention, incorrect warnings aredetected based on the chronological profile of the relevance measure.Information is advantageously output as a function of the relevancemeasure determined. (Thus, for example, information whose relevancemeasure is too low is not output.)

In one advantageous embodiment of the invention, the output ofinformation to the driver is terminated as soon as a warning isdetermined to be incorrect. In this context, it is advantageous if, assoon as the output of information is terminated owing to an incorrectwarning, the driver is explicitly informed, by means of a directlyfollowing information output, that the previously reported hazard is nolonger relevant to him.

The invention helps to prevent, for example, mass pileups of vehiclessuch as can occur, for example, on freeways, frequently due to poorvisibility conditions (for example fog), sections of road with poorvisibility (for example, before a curve which cannot be seen intosatisfactorily) or due to traffic disruption (for example end ofcongestion or roadworks). The invention makes it possible for thedrivers of following vehicles to detect hazards ahead and to brake theirvehicle in time to avoid a collision. In one embodiment the vehicle canbe braked automatically, by an intervention in the vehicle controlsystems.

In another embodiment of the invention, the hazard warning devicecomprises a data transmitter which is triggered, for example, by thehazard warning system of the vehicle. If the hazard warning system of avehicle is triggered in this embodiment, a corresponding radio messageis emitted to all the vehicles in the vicinity of the transmittingvehicle. The transmitted data of each transmitter includes its currentspeed and its position chain. It is also possible for the transmitter totransmit its identification number and/or a type of hazard.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The single figure of the drawing is a block diagram of a device forradio-based issuing of warnings of hazards, according to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

As shown in the figure, the radio based hazard warning device accordingto the invention comprises a data receiver unit 10, data transmitterunit 15 and a computer unit 20. The device is preferably connected to anavigation system 30, an output unit 40, an activation device 50 and asensor unit 60 via a vehicle bus system. The sensor unit may comprise aplurality of different sensors, such as a crash sensor, a speed sensoretc. The activation device 50 may be, for example, the hazard warningsystem of the vehicle.

The position information which is output by a transmitting vehicleadvantageously includes a directional course of the vehicle, formed fromthe direction of travel and speed of the vehicle at various times.Alternatively (or in addition), information about the position isgenerated by a navigation system 30, advantageously using a locatingdevice, for example GPS. The type of road and the direction of travelcan also be determined using a navigation system 30. An example of thedetermination of the position, type of road and direction of travel bymeans of a navigation system 30 is described in International patentdocument WO 01/61668 A1, the disclosure of which is incorporated byreference, as fully as if set forth in its entirety herein. An exampleof the determination of the position, type of road and direction oftravel using directional courses of vehicles is found in European patentdocument EP 0 927 983 A2, the disclosure of which is also incorporatedby reference.

The position chain of a vehicle is composed of a sequence of points forwhich information relating to the position of the vehicle is present.The position chain may be a directional course and/or a sequence ofpositions which are determined by means of a locating system ornavigation system 30. The position chain describes the geometry of theroute covered by the transmitting vehicle (the “transmitter”) in therecent past. By comparing its own position chain with the position chainof the transmitter, the receiving vehicle (the “receiver”) can checkwhether the routes covered theretofore by both vehicles are identical,and whether the transmitter is ahead of the receiver (that is,downstream of it), or behind it (upstream of it). The result of thiscomparison is expressed by a relevance measure. For example, on freewaysit is possible to detect whether the transmitter is located on the sameroadway ahead of the receiver or on the opposite roadway. If thetransmitter is located ahead of the receiver on the same roadway, therelevance measure is large and the driver of the receiver must be warnedbefore the signaled hazard. If the transmitter is located behind thereceiver or on the opposite roadway, the relevance measure is small andthe received hazard message has no significance for the driver of thereceiver.

A further advantage of the device described here is the ability todetect incorrect warnings (that is, a warning regarding a hazard whichis not located on the driver's future route). There are certainsituations in which an incorrect warning is unavoidable. If for example,the transmitter is located just beyond a fork in the roadway (forexample, on the left hand branch), the driver of the receiver must bewarned of the signaled hazard even if at the time when the warning istriggered it is not yet known whether the receiver will travel on theleft-hand or right-hand branch of the fork. Irrespective of the futuredecision to make a turn, the relevance measure of the transmitter issufficiently large to trigger a warning.

However, after the fork is reached the further course of the relevancemeasure depends on whether the receiver travels along the left-hand orright-hand branch of the fork. In the first case, the position chains ofthe transmitter and receiver continue to correspond satisfactorily, therelevance measure remains high and the warning is maintained. In thesecond case, the position chains of the transmitter and receiver divergeand the relevance measure drops. If it drops below a given thresholdvalue, it can be assumed that the transmitter and receiver are locatedon different routes, and the warning has been incorrectly triggered. Anincorrect message is therefore detected by the trailing edge of therelevance measure. In this case, not only is the warning terminated, butthe driver is also explicitly informed that the previously signaledhazard is no longer relevant to him. This prevents the driver's losingconfidence in the radio warning system due to incorrect warnings whichare unavoidable under certain circumstances. It also prevents thedriver's being surprised by the apparently inexplicable disappearance ofthe warning.

The hazard warning can also be refined by routes information which canbe obtained, for example, from a digital road map. On the one hand, itis possible to use the route information to predict the future route ofthe transmitter, at least as far as the next intersection point. As aresult, the position chain of the transmitter can be lengthened and thereliability of the relevance measure, which depends on the length ofoverlap between the position chains of the transmitter and receiver, canbe increased.

Furthermore, by previewing the route, it is possible to determine thedistance between the transmitter and receiver more accurately becausethe precise geometry of the part of the route lying between the twovehicles is known. Likewise, incorrect warnings can in certainsituations be avoided by means of the route information. If, forexample, it is detected that a transmitter is located after a fork, thenonly warning levels of high urgency can be permitted, ensuring that thedistance threshold for the triggering of the warning is located beyondthe fork so that it is possible to wait to see whether after the forkthe receiver will travel on the same branch as the transmitter or selectthe other alternative route.

Advantageously, the driver is warned as long as radio messages arereceived and the transmitter is located ahead of the receiver. However,it is necessary to take into account the fact that temporary disruptionof the communication link may occur as a result of external influences.For this reason, if no further radio messages are received, this isinitially interpreted as a temporary interruption in the communicationlink and not as a deactivation of the transmitter. The warning isfurthermore maintained and the relative movement of the receiver withrespect to the transmitter is continued on the assumption that thetransmitter continues moving with its last-known speed. The warning isterminated only if no further radio messages are received for asufficiently long time, but at the earliest after a minimum warningtime, which ensures that the driver can also perceive the indicatedwarning.

A warning is also terminated if the driver of the receiver indicates, byswitching on his own hazard warning system, that he has detected thesignaled hazard. The switching on process of the hazard warning system,and not the state “hazard warning lights on” is advantageously used as acriterion for the termination of the warning since otherwise the driverwould not receive any warning if he were to approach a transmitter withhis hazard warning system already switched on (because, for example, heis towing another vehicle). The possibility of switching on his ownhazard warning system is an advantageous way for the driver toacknowledge a warning, and thus terminate it manually. Restriction tothis type of acknowledgement keeps the system simple; however, morewide-ranging operating control actions are possible.

A warning is also terminated automatically if the approach speed of thereceiver to the transmitter or the absolute speed of the receiver becomevery low. This prevents, for example, a display in the vehicle beingblocked for an unnecessarily long time.

Scenarios are possible, for example when a vehicle is approaching theend of a traffic jam, in which a plurality of transmitters emit radiomessages simultaneously.

With the system described here, the radio messages of any desired numberof transmitters can be processed in parallel. Successive radio messagesfrom the same transmitter are recognized on the basis of their commonidentification number. At first, individual checking is carried out foreach transmitter to determine which relevance measure is to be assignedto it.

In order to determine the chronological profile of the relevance measurefor each of the transmitting vehicles, the relevance measure isdetermined for each transmitting vehicle at time intervals. By means ofthe chronological profile it is then possible, for example, to determinewhich messages are incorrect messages.

In terms of the types of hazard a distinction is made between a generalhazard, a virtual warning triangle, an accident and roadworks. Thegeneral hazard is transmitted if the driver has manually triggered thehazard warning system and the engine of the vehicle is running (forexample when approaching the end of a traffic jam). The virtual warningtriangle type of hazard is transmitted if the driver has triggered thehazard warning system manually and the engine of the vehicle is off (forexample because the vehicle has broken down). The accident type ofhazard is transmitted if the hazard warning system has been triggeredautomatically by the crash sensor of the vehicle. And finally, theroadworks type of hazard is not transmitted by vehicles but rather bybeacons which mark the start of roadworks.

The driver can be informed visually and/or audibly about the hazardlying ahead. The visual warning is implemented by a display which ismounted in the vehicle. Such a display is preferably integrated in thecombination instrument and is thus located in the primary field ofvision of the driver. At this location, the attention of the driver canadvantageously be drawn to the hazard warning by means of a visualoutput. The visual warnings can also be supplemented by audible signalsor voice outputs in order to ensure reliable perception of the warningeven if the driver's gaze is averted from the combination instrument(because he is, for example, operating the radio or some other operatingdevice mounted in the center console or is concentrating completely onobserving the surrounding traffic situation).

The foregoing disclosure has been set forth merely to illustrate theinvention and is not intended to be limiting. Since modifications of thedisclosed embodiments incorporating the spirit and substance of theinvention may occur to persons skilled in the art, the invention shouldbe construed to include everything within the scope of the appendedclaims and equivalents thereof.

1-12. (canceled)
 13. A radio-based device for issuing hazard warninginformation to a driver of a receiving vehicle having a data receiverwhich receives hazard data from a data transmitter of at least one othervehicle, and evaluates the received data; wherein: received dataincludes information regarding position, speed and direction of travelof the at least one other vehicle; based on (i) the received data fromthe at least one other vehicle, (ii) information regarding position,speed and direction of travel of the receiving vehicle, a relevancemeasure is determined in the receiving vehicle, which relates to whetherthe at least one other vehicle is located on a section of road lyingahead of the receiving vehicle; and a chronological profile of therelevance measure is determined by repeatedly determining the relevancemeasure.
 14. The device as claimed in claim 13, wherein thechronological profile of the relevance measure is stored in thereceiving vehicle.
 15. The device as claimed in claim 13, whereinincorrect warnings are detected based on the chronological profile ofthe relevance measure.
 16. The device as claimed in claim 13, whereinthe received data comprise a position chain of the at least one othervehicle.
 17. The device as claimed in claim 13, wherein a future routeof the receiving vehicle is estimated in advance in the receivingvehicle.
 18. The device as claimed in claim 17, wherein the relevancemeasure is determined from the received data of the at least one othervehicle and the estimated future route of the receiving vehicle.
 19. Thedevice as claimed in claim 13, wherein the hazard warning information isoutput as a function of the determined relevance measure.
 20. The deviceas claimed in claim 19, wherein the information output is terminated assoon as it has been detected as an incorrect warning.
 21. The device asclaimed in claim 20, wherein after the information output has beenterminated, the driver is informed by a further information output thata previously signaled hazard warning information is no longerapplicable.
 22. The device as claimed in claim 13, wherein data isreceived from data transmitters of a plurality of other vehicles, and isevaluated.
 23. The device as claimed in claim 13, wherein thechronological profile of the relevance measure is determined in eachtransmitting vehicle from which data is received.
 24. The device asclaimed in claim 13, further comprising: a data transmitter which, whenactivated, outputs data to issue warnings of hazards to other vehicles;wherein the transmitted data comprise information about position, speedand direction of travel of the transmitting vehicle.
 25. A method ofissuing hazard warning information to a driver of a receiving vehicle,comprising: a receiving on board said receiving vehicle receivinginformation transmitted from at least one other vehicle regarding ahazard in a vicinity of said at least one other vehicle; said receiveralso receiving from said at least one other vehicle informationregarding position, speed, and direction of travel of said at least oneother vehicle; based on said position speed, and direction informationfrom said at least one other vehicle, and on information regardingposition, speed and direction of travel of the receiving vehicle,determining a relevance measure that is indicative of a likelihood thatthe receiving vehicle will encounter said hazard; determining achronological profile of the relevance measure, based on repeatedrelevance measure determinations; and issuing a hazard warning to saiddriver as a function of said chronological profile of said relevancemeasure.
 26. The device as claimed in claim 25, wherein a future routeof the receiving vehicle is estimated in advance in the receivingvehicle.
 27. The device as claimed in claim 26, wherein the relevancemeasure is determined from the received data of the transmitting vehicleand the estimated future route of the receiving vehicle.